Process of making alkyl chlorides



Patented Sept. 29, 1931 Ho Drawing.

UNITED. STATES RAT-BN1? orrice JOHN ram, or WILMINGTON, nnLawann, assrenon 're a. ,1. DU POINT nn uamouas a COMPANY, or wnumerou, DELAWARE, aconrona'rrou or DELAWARE rnoc'ass or amxme anm o'nnoamns of a lchlorides and especially of such chlori es in which the alky roupcontains less than three carbon atoms, uch for example 'as methylchloride and ethyl chloride, and includes as the preferred embodimentheating together an alkali-metal chloride, sul

- phuric acid and an alcohol having preferably one or two carbon atoms,and bringing the resulting vapor mixture, comprising a] l chloride,alcohol, h drogen c loride an water, into contact wit a metal chloride(such as ,zinc chloride or ferric chloride) heated to a temperaturebetween 100 and 150 C., said metal chloride being in the form of anaqueous solution. 3 1 It is known th t ethyl chloride can be made bheating dilute sulphuric acidwith sodium cllloride and alcohol. Accordinto that process the alcohol must be fed s owly and the ethyl chloridemust go through a reflux condenser in order to prevent alcohol fromescaping unchanged from the reaction vessel. It takes to hours to finishone batch and there has been no known way of speeding up the reaction. a

I have now discover'eda method of carrying out this process in a muchshorter time, about one fourth to one fifth of the time mentioned above,thus increasing the production of the equipment four to five fold. ,This

new method is characterized by the use of a second reaction vesselcontaining a ferric chloride or a zinc chloride solution which ispreferably kept at a temperature between 110 and 150 C. The vaporscoming from the. first reaction vessel comprising ethyl chloride,alcohol, hydrogen chloride, and water are carried through the secondreaction vessel without being refluxed on leaving the first vessel. Themetal chloride solution in" the second vessel absorbs alcohol andhydrogen chloride and remotes further reaction between them an at ahigher temperature than before. Care should be taken that the vaporsescaping from the first vessel contain at leastone equivalent ofhydrogen chloride for each equivalent of alcohol carried at the samctime in the mixture. This can easily be accomplished by regulating theligible quantity of alcohol.

Application ma mm: 1a, 1925. Serial no. 18,808.

temperature and the rate of feeding sul-- phuric acid to the firstvessel. The vapors leaving the second vessel contain only a neg-' Theyare washed successively by water and concentrated sulphuric acid to freethem from" hydrochloric acid and ether, andflare then condensed.

" Ewampl .-An acid proof vessel is charged with salt (gsodium chloride)and dilute sulphurie ac'i (e. g from40% to 50% stren and heated up to 90C., suflicientdilute liz id being used to wet the salt and facilitatethe heating thereof. To this mixtlire I let slowl run in a mixture ofstrong sulphuric acid and alcohol. The escaping vapors are carried throuh the zinc chloride solution in the secon reaction vessel whichpreviously has been heated to 135 C This temperature is maintained durinthe'whole rocess. When the sulphuric aci -alcohel mixture has been fedin, the temperature-1n the first reactionpot is aduall raised till thedevelopment of ethy chlori e is finished.

The'ethyl chloride-leavin the second reaction vessel is accompanied ywater, hydrochloric acid, and traces of alcohol and ether,

and is freed from them by successive] wash ingd with water andconcentrated s phuric aci Since, in the above example, the temperatureofethe zinc chloride solution is maintained constant thruout theoperation it inevitably follows that, after the process is underway anda state of equilibrium established,'the water which is a product of thereaction will be removed from the catalyst solution as fast and only asfast, as it is formed. That this must be so is obvious when it isconsidered that any tendency of the water to accumulate in the catalystsolution would be counteracted by a corresponding loweringof the boilingpoint and a resulting increasein the amount of water boiled oif, whileany tendency of the water content to diminish would be counteracted by acorresponding rise of the boilin point of the solution and is' keptwithin t e preferred limits so long as the temperature range of'110150G. is observed.

In the new process, as illustrated by the above example, the totalquantity of sul phuric acid' used should be the molecular equivalent ofthe quantity of salt used; but

the quantity of sulphuric acid used should be in excess of the molecularequivalent of the alcohol used by from about'lfi to 20%. The acid addedin admixture with alcohol should be strong acid, for example between 90and 100% referably 93% strength, although if desired it may be less than90% strength. The aqueous zinc chloride solution, the concentration ofwhich will of necessity depend upon the temperature of operation isdesirably maintained at a temperature between about 110 and150 0., andpreferably (for ethyl chloride) at 135 (1., or (for methyl chloride) at120 C. v

Although I have described 111 process in considerable detail, it will beun erstood that my invention is not limited to the particular conditionsspecified in the above Specific example, but includes various changesand modifications not excluded by the terms of the appended claims.Instead of zinc chloride, I may use. in water solution, another metalchloride, for example ferric chloride, whose aqueous solution is'capable of promoting reaction between an alcohol and hydrogen chlorideat moderately high temperatures.

I claim:

1. The rocess of makin an alkyl chloride whic comprises heatlng togethersodium chloride, sulphuric acid, and an alcohol to form a vapor mixturecontaining an alkyl' chloride, alcohol, hydrogen chloride, and water,and bringing said vapor mixture in contact with an aqueous metalchloride solution capable of prompting reaction between said alco 01 andsaid hydrogen chloride, said solution being maintained at a temperature7 between 100 and 150C.

2. A process as defined in claim 1 in which the vapor mixture is broughtin contact with an aqueous zinc chloridesolution maintained at atemperature between 100 and 150 C.

3. In the process of making an alkyl chloride, the step which comprisespassing a vapor mixture containing an alcohol and hydrogen chloride intoan aqueous metal chloride solution capable of promoting reaction betweensaid alcohol and said hydrogenchloride at a moderately hightemperature,'said solution being maintained 4. In the process of makingan alkyl chloride, the step-which comprises passing a which comprisesheatin vaponmixture containing an alcohol and hydrogen chloride into anaqueous zinc chloride solution maintained at a temperature between 110and 150 C. 5., The process ofmaking ethyl chloride together sodiumstrong sulphu 0 acid, and ethyl form a vapor containing chloride alcoholto an aqueous zinc chloride solution maintained at a temperature between110 and 150 C.

. ride and water, an bringing said vapor mixture in contact with anaqueous metal chloride solution maintained at such a temperature thatthe solution is capable of promotin reaction between said ethyl alcoholand sai hydrogen chloride.

r 6. A process as defined in claim 5 in which the vapor mixture isbrought in contact with at a temperature between 110 and 150 C.

7. In the process of making ethyl chloride the step which comprisespassing a vapor mixture containing ethyl alcohol and hydrogen chlorideinto an aqueous metal chloride solution capable. of promoting reactionbetween said ethyl alcohol and hydrogen chloride, at agnoderately hightemperature, said solution being maintained at a temperature between 110and 150C.

8. In the process of making ethyl chloride the step which comprisespassing a va or mixture containing ethyl alcohol and by rogen chlorideinto an aqueous zinc chloride solution at a temperature of about 135 C.

9. A process as set forth in claim 1 in which the vapor mixture containsat least one mo- 10. A process asset forth in claim 3 in which the vapormixture contains at least one molecular equivalent of h drogen chloridefor each molecular equiva ent of alcohol present. a

11. A process as set forth in claim 5 in which the vapor mixturecontains at least one molecular equivalent of hydrogen chloride for eachmolecular equivalent of alcohol present. I

12. A process as set-f rth in claim 7 in which the vapor mixturecontains at least one molecular equivalent of hydrogen chloride for eachmolecular equivalent of alcohol present.

18. The process of making ethyl chloride which comprises heating toabout 90 C. a mixture of 2 parts (by weight) of salt with about gnepartmf dilute sul h'uric acid, adding graduall to the heate mass .amixture of et yl alco ol with concentrated sulphuric acid, \and assinthe resulti va ors ion through a z nc ch oride solution eate to 14. Arocess as defined in claim-13 in which, a r the addition of alcohol andsultion being maintained at a temperature between 110 and 150 C.

16. In the process of making an alkyl chloride which involves reactingan alcohol and hydrogen chloride in the presence of an aqueous metalchloride solution which is liquid at normal temperatures, theimprovement which comprises simultaneously passing hydrogen chloride andvaporous ethyl alcohol into said solution while removing onl the watervapor and ethyl chloride evo ved, whereby the water content of saidsolution remains substantially constant and the process may be operatedcontinuously.

17. In the process of making an alkyl chloride which involves reactingan alcohol and hydrogen chloride in the presence of an aqueous metalchloride solution which is liquid at normal temperatures, theimprovement which comprises simultaneously passing vaporous ethylalcohol and at least a molecularly equivalent quantity of hydrogenchloride intothe said solution while maintainin it at a temperaturebetween 110150 0., an remov- 26 ing the water vapor and ethyl chlorideevolved;

18. In the process of making ethyl chloride which involves reactingethyl alcohol and hydogen chloride in the presence of an aque- 30 ouszlnc chloride solution which is liquid at normal temperatures theimprovement which comprises simultaneously passing vaporous ethylalcohol and at least a molecularl equivalent quantity of hydrogenchloride into the said solution while maintaining it at a temperature ofabout 135 C. and removing the water va or and ethyl chloride evolvedwhereby t e water content of the zinc chloride solution remainssubstantially constant and the process maybe operated continuously.

In testimony whereof I afiix m signature.

J OH FREI.

tion being maintained at a temperature between 110 and 150 C.

16. In the process of making an alkyl chloride which involves reactingan alcohol and hydrogen chloride in the presence of an aqueous metalchloride solution which is liquid at normal temperatures, theimprovement which comprises simultaneously passing hydrogen chloride andvaporous ethyl alcohol into said solution while removing 0111 the watervapor and ethyl chloride evo ved, whereby the water content of saidsolution remains substantially constant and the process may be operatedcontinuously.

17 In the process ofmaking an alkyl chloride which involves reacting analcohol and hydrogen chloride in the presence of an aqueous metalchloride solution which is liquid at normal temperatures, theimprovement which comprises simultaneously passing vaporous ethylalcohol and at least a molecularly equivalent quantity of hydrogenchloride into the said solution while mamtainin it at a temperaturebetween 110150 (1., an removing the water vapor and ethyl chlorideevolved;

18. In the process of making ethyl chloride which involves reactingethyl alcohol and hydogen chloride in the presence of an aqueous zincchloride solution which is liquid at normal temperatures the improvementwhich comprises simultaneously passin vaporous ethyl alcohol and atleast a molecu arly equivalent quantity of hydrogen chloride into thesaid solution while maintaining it at a temperature of about 135 C. andremoving the water va or and ethyl chloride evolved whereby t e watercontent of the zinc chloride solution remains substantially constant 40and the process may be operated continuously.

In testimony whereof I aflix m signature.

J OH FREI.

CERTIFICATE or CORltECTlON.

Patent No. 1,824,951; I

JOHN FREI.

Granted September 29, 1931, to

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1,line 97, after "solution" insert a period and the words The watercontent therefore remains substantially constant so long as agiventemperature is maintained; page 2, line 39, claim 1, for prompting"read promoting; line 126, claim 15, for "of" read a; and that the saidLetters Patent should he read with these corrections therein that thesame may conform to the record of the case in the Patent 0ffice.

Signed and sealed this 17th day of November, A. D. 1931.

M. J. Moore,

(Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. 1,824,951. Granted September 29, 1931, to

JOHN FREI.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1,line 97, after "solution" insert a period and the words The watercontent therefore remains substantially constant so long as a giventemperature is maintained; page 2, line 39, claim 1, for prompting" readpromoting; line 126, claim 15, for "of" read a; and that the saidLetters Patent should be read with these corrections therein that thesame may conform to the record of the case in the Patent 0f fice.

Signed and sealed this l7th day of November, A. I). 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents.

